Analyzers featuring automatic scanning means are known which can process a number of samples to be analyzed.
EP-PS 0 096 065 discloses a means for automatically scanning test tubes which are held in an elongated tray and fed to a processing station in which the presence or absence of a test tube in the tray is detected by means of an opto-electronic sensor means. For this purpose, the side walls of the individual test tube receptacles are provided with apertures.